Stimulants: Cocaine, Amphetamines, Methamphetamine and MDMA

Cocaine is the principal alkaloid of Erythroxylum coca, a shrub native to the Andean highlands of South America. The genus Erythroxylum contains over 250 species, but three carry commercially relevant cocaine levels: E. coca var. coca (cultivated in Peru and Bolivia, predominantly for traditional chewing and coca tea), E. coca var. ipadu (Amazon basin, lower alkaloid content), and E. novogranatense var. novogranatense (Colombia, the dominant species in the industrial trafficking supply chain). The alkaloid content of leaves ranges from 0.5 to 1.5 per cent w/w; Colombian material typically sits at 0.8-1.2 per cent.

The extraction sequence from leaf to cocaine hydrochloride, sometimes called the "Colombian process" in UNODC technical documentation:

1. Maceration: leaves are mixed with water and a base (sodium carbonate, calcium oxide / quicklime) to deprotonate the cocaine alkaloid (pKa 8.6) from its salt form in the leaf, freeing the freebase.
2. Solvent extraction: gasoline (petrol), kerosene, or ether extracts the freebase cocaine and other neutral alkaloids (ecgonine derivatives, cinnamoylcocaine, benzoylecgonine in small amounts) from the basic aqueous slurry.
3. Acid wash: the solvent layer is washed with dilute sulfuric acid (or tartaric acid), which back-extracts cocaine into the aqueous acid phase as cocaine sulphate (the "coca paste" intermediate in South American drug chemistry).
4. Basification: the acid layer is made basic with ammonia or sodium carbonate to precipitate cocaine freebase as a white solid (cocaine sulphate precipitation). This intermediate is called pasta base (cocaine base paste) and is typically 40-90 per cent purity.
5. Conversion to hydrochloride salt: cocaine freebase is dissolved in a solvent (acetone, ether) and treated with hydrochloric acid, precipitating cocaine hydrochloride (the white crystalline powder) at typical purities of 80-95 per cent.

Crack cocaine is produced by a simple reversal: cocaine HCl is dissolved in water, treated with baking soda (sodium bicarbonate) or ammonia, and the freebase that precipitates is dried. The "crack" sound (and name) comes from the popping of sodium bicarbonate residues in the freebase when heated. Crack is smoked because the freebase has a melting point of 98°C and volatilises without decomposition; the HCl salt cannot be smoked effectively because it melts at 195°C with decomposition. This physical chemistry distinction is what drives the crack vs powder distinction in routes of administration and, consequently, in social epidemiology.

From a casework standpoint: cocaine HCl is confirmed by the Scott cobalt thiocyanate test (cobalt thiocyanate in aqueous solution, then glycerine, then saturated sodium chloride; true positive gives blue precipitate in the organic layer), Marquis (orange-brown, differentiating from heroin's purple-black), and GC-MS (molecular ion m/z 303, base peak m/z 182 from benzoyl fragment loss, plus m/z 82, 94). For the full SWGDRUG category tier decision logic governing these steps, see SWGDRUG Identification Tiers and the UV-TLC-GC-MS-LC-MS/MS Workflow. Crack (cocaine freebase) gives the same GC-MS spectrum but may show different cutting-agent profiles. The freebase has higher GC-MS volatility and elutes approximately 0.5 minutes earlier than a polar reference standard injected in methanol; injection in ethyl acetate is recommended for crack to avoid conversion artefacts.

The cocaine supply chain involves cutting (adulteration to extend the product) at multiple stages from production to street level. The adulterant profile changes as the product moves down the supply chain and is therefore a fingerprint of how far along the distribution network a seized sample sits. The SWGDRUG identification tier workflow is applied systematically to both the principal compound and each detected adulterant.

At the production level: pharmaceutical adulterants added in South American laboratories include levamisole (a veterinary antihelminthic, found in approximately 80 per cent of cocaine samples in North American and European monitoring since 2014), phenacetin (a now-banned analgesic with cocaine-potentiating perceived effect), and aminorex (a stimulant generated as a metabolic product of levamisole). Levamisole's prevalence is not fully explained: hypotheses include use as an immune system potentiator (disputed), co-extraction from coca plants grown in soils treated with levamisole-based pesticides (partially supported by agrochemical data), and direct addition at the production stage to increase perceived potency or reduce the cost of pure cocaine per weight unit.

At the trafficking and mid-level distribution stage: local anaesthetics (benzocaine, procaine, lidocaine) are added for their numbing effect that mimics cocaine's topical effect when rubbed on gums, making adulterated product more convincing to buyers. Benzocaine is the most common adulterant in UK and EU seizures by weight.

At the street level: mannitol, lactose, and inositol are used as bulking agents. These inert sugars give the product a visual and tactile texture similar to cocaine powder.

Isotope ratio mass spectrometry (IRMS) for source attribution: Stable isotope ratios (13C/12C expressed as delta-13C in per mille relative to Vienna Pee Dee Belemnite, and D/H) in cocaine reflect both the photosynthetic pathway of the coca plant (C3 pathway, with characteristic delta-13C around -28 to -32 per mille) and the local water and soil isotopic signatures. Colombian, Peruvian, and Bolivian cocaine populations have statistically distinct delta-13C profiles in the benzoyl ester and ecgonine methyl ester moieties. The Thermo Scientific DELTA V Advantage isotope ratio mass spectrometer, coupled with a preparative GC inlet for compound-specific IRMS (CSIA), is the instrument of choice. UNODC's Isotope Ratio Data Bank and the European Forensic Isotope Ratio Reference Database (EFI-RRD) provide reference isotope fingerprints for source-region comparison.

The 2020 Encrochat operation (a French-led law enforcement operation that compromised the Encrochat encrypted phone network used by European drug traffickers) produced a dataset of seized cocaine exhibits with documented supply chains. Isotope ratio analysis on these exhibits, performed by the Dutch NFI and the Bundeskriminalamt (BKA), confirmed the source attribution method's concordance with intelligence data: samples attributed to Colombian origin by IRMS matched supply chain intelligence pointing to FARC-dissident-affiliated production groups in the Nariño and Putumayo departments.

Amphetamine (alpha-methylphenethylamine) and methamphetamine (N-methyl-alpha-methylphenethylamine) are chiral molecules, each existing as two non-superimposable mirror-image isomers (enantiomers): the dextrorotatory (d-, or R-,) and levorotatory (l-, or S-,) forms. The pharmacological consequences of this chirality are profound:

• d-Amphetamine (R-(-)-amphetamine, the levorotatory optical isomer; note: the R-configuration is conventionally the dextrorotatory form for amphetamine): the dominant CNS stimulant; the active form in Adderall (a 3:1 d:l mixture) and Dexedrine.
• l-Amphetamine: weaker CNS effect; used as the racemic mixture in Benzedrine historically; less controlled in some jurisdictions.
• d-Methamphetamine (S-(+)-methamphetamine): the potent CNS stimulant form; street methamphetamine is predominantly this enantiomer. Desoxyn (brand-name pharmaceutical methamphetamine) is d-methamphetamine.
• l-Methamphetamine (R-(-)-methamphetamine): very weak CNS activity; found in over-the-counter Vicks Inhaler (methamphetamine nasal decongestant, still available OTC in the US and some other countries). In the US, l-methamphetamine is not scheduled under the CSA at the federal level.

In casework, this distinction matters when a defendant claims that a methamphetamine seizure is consistent with OTC Vicks Inhaler rather than illicit product. The racemic mixture (50:50 d:l) produced by P2P synthesis or other non-stereoselective routes, and the nearly pure d-enantiomer produced by pseudoephedrine reduction (a stereospecific route), allow enantiomeric analysis to distinguish synthesis route:

• Pseudoephedrine reduction (Birch / Nazi method, catalytic hydrogenation): stereospecific, yields predominantly d-methamphetamine (>95 per cent d-enantiomer, enantiomeric excess >90 per cent d).
• P2P (phenylacetone + methylamine, reductive amination): non-stereospecific, yields racemic or near-racemic methamphetamine (40-60 per cent d).

Chiral gas chromatography on a Chirasil-DEX CB column (Agilent) or a Cyclosil-B column resolves d- and l-methamphetamine to baseline under standard conditions (column temperature 120°C, carrier He at 1.0 mL/min). The ratio is expressed as enantiomeric excess (ee). A high ee strongly implicates pseudoephedrine-reduction route (and therefore ephedrine/pseudoephedrine as the precursor, a controlled substance globally). Near-racemate implicates P2P or alternative non-stereospecific synthesis.

The clandestine synthesis of amphetamines has evolved through at least four major route generations, each driven by precursor scheduling that closed off the previous route and pushed chemists toward alternatives.

Leuckart reaction (amphetamine and methamphetamine): Phenylacetone (phenyl-2-propanone, P2P, also called benzyl methyl ketone, BMK) reacts with formamide in the Leuckart reaction to give an N-formyl intermediate, which is hydrolysed to give amphetamine, or reacts with N-methylformamide to give methamphetamine. The route is non-stereospecific, yielding racemic product. P2P was heavily used in European clandestine labs before it was placed under UN Convention Table I control in 1988 and under the EU Drug Precursors Regulation. After P2P scheduling, European labs shifted to other precursors; however, P2P synthesis has resurged since approximately 2020, with the DEA documenting a shift in the US methamphetamine supply from pseudoephedrine-reduction d-meth back toward racemic P2P-route meth. The DEA's 2022 drug threat assessment attributes this shift to enhanced pseudoephedrine/ephedrine scheduling reducing availability.

Birch reduction / Nazi method (methamphetamine): Ephedrine or pseudoephedrine is reduced using lithium or sodium metal dissolved in anhydrous ammonia (the Birch reduction conditions), with a proton source (t-BuOH or i-PrOH). The method is stereospecific: starting from pseudoephedrine (the 1S,2S enantiomer), the product is d-methamphetamine with high enantiomeric purity. This route dominated US methamphetamine production in the 1990s-2000s and is sometimes called the "Nazi method" (though the historical link to World War II German production is largely myth). Characteristic impurities from the Birch route include phenylacetone (trace) and 1-phenyl-2-propanol (from incomplete reduction).

Pseudoephedrine/ephedrine catalytic hydrogenation: Pseudoephedrine or ephedrine is treated with hydriodic acid (HI) and red phosphorus (or white phosphorus) as a catalyst, with HI generated in situ. This is a variation on the P-red method; the product is predominantly d-methamphetamine from pseudoephedrine. The Combat Methamphetamine Epidemic Act (US, 2005) placed pseudoephedrine and ephedrine in Schedule V of the CSA with purchase limits (3.6 g per day, 9 g per 30 days from behind-the-counter pharmacy sales), requiring ID verification and electronic logging. This is why pseudoephedrine-containing cold medicines (Sudafed) require pharmacy counter access in the US. India's NDPS Schedule III controls pseudoephedrine and ephedrine as controlled precursors; their import and export requires NCB/DEA country authorisation.

P2P reductive amination: Phenylacetone (P2P, BMK) is reductively aminated with methylamine and sodium cyanoborohydride or catalytic hydrogenation (Pd/C, H2) to give methamphetamine. Non-stereospecific. Characteristic impurities: dimethylamphetamine (from bis-methylation), unreacted P2P.

Identifying the synthesis route from the exhibit product uses: (1) enantiomeric ratio (chiral GC); (2) impurity profile (GC-MS detection of route-specific byproducts: P2P route shows dimethylamphetamine impurity; Birch route shows 1-phenyl-2-propanol; pseudoephedrine route may show residual pseudoephedrine). This impurity profiling is the basis for UNODC's methamphetamine signature program, which uses GC-MS data from national laboratories to build a supply-chain intelligence picture.

MDMA (3,4-methylenedioxymethamphetamine) and its desmethyl analogue MDA (3,4-methylenedioxyamphetamine) belong to the methylenedioxy-substituted phenethylamine family. MDMA is the most commonly seized entactogen globally; EMCDDA data shows approximately 12.3 million European adults (aged 15-64) reporting lifetime MDMA use, with an estimated 2.3 million reporting use in the last year. MDA is less common in current seizures but was the dominant compound in the 1960s-1970s before MDMA was popularised.

The key precursor for MDMA synthesis is the methylenedioxyphenyl moiety, introduced via either safrole (4-allyl-1,2-methylenedioxybenzene, extracted from sassafras oil from Cinnamomum camphora trees in Cambodia, Vietnam, and Brazil) or isosafrole (the double-bond isomer). Safrole was placed under Table I of the UN 1988 Convention following evidence of its use as the primary MDMA precursor in the late 1980s and early 1990s. In 2008, UNODC, the Australian Federal Police, and Cambodian authorities disrupted safrole oil trafficking from Cambodia, which had supplied European MDMA labs.

After safrole scheduling, clandestine chemists shifted to precursor substitutes:

• PMK (piperonylmethylketone, 3,4-methylenedioxyphenylacetone): the P2P analogue for the methylenedioxy series; placed under international control but still the dominant MDMA precursor in European production. PMK-glycidate, a PMK derivative, was developed as a PMK substitute after PMK scheduling. Both are now controlled under EU Drug Precursors Regulation 2016/277 and the 2021 supplement.
• MDP2P (3,4-methylenedioxyphenyl-2-propanone): another name for PMK; the same compound. Listed in the INCB (International Narcotics Control Board) pre-export notification system.

MDMA synthesis routes: the Wacker oxidation of safrole or isosafrole to PMK, followed by reductive amination with methylamine (analogous to the P2P-methylamine route for methamphetamine). The product is racemic MDMA; there is no stereospecific route that dominates the clandestine supply, so the enantiomeric ratio of seized MDMA is typically near-racemic (unlike d-meth from pseudoephedrine reduction). Both the R- and S-enantiomers of MDMA have similar entactogenic activity. MDMA is Schedule I under the US CSA and Class A under the UK MDA 1971; its commercial quantity threshold under India's NDPS Act is 10 g, as set out in Controlled Substances Schedules: NDPS, CSA, MDA and EU Framework.

Casework identification: Scott test is negative (cobalt thiocyanate is specific for cocaine). Marquis reagent gives a distinctive purple-black for MDMA (slower than heroin; approximately 30-60 seconds). Mecke reagent gives blue-green. GC-MS: MDMA molecular ion m/z 193, base peak m/z 58 (CH2=NHCH3+, methyliminium cation). MDA differs by 14 Da (m/z 179) with base peak m/z 44. The 14 Da difference and the base peak at m/z 44 vs 58 definitively distinguishes MDA from MDMA. LC-MS/MS is used for quantification in tablet content analysis.

MDMA tablet analysis: seized MDMA tablets show enormous variation in content. A 2023 EMCDDA drug market report cites a range from 50 mg to 340 mg MDMA per tablet in EU seizures, with an average of approximately 145 mg. Tablets exceeding 200 mg (dubbed "super pills") are associated with overdose risk. The Bruker Alpha FTIR-ATR is used by Dutch, Belgian, and German drug-checking services (pill-testing programmes) for rapid MDMA confirmation; dose quantification requires LC-MS/MS. India does not have an operational pill-testing programme; MDMA seizures go directly to FSL for identification under NDPS psychotropic schedule provisions.

Stimulant casework combines classical colour chemistry, chromatographic separation, and mass spectrometric confirmation, with chiral GC and IRMS as method extensions for specific analytical questions.

Cocaine workflow: Scott test (presumptive); GC-MS (Category A confirmation, Agilent 7890/5977, HP-5MS, molecular ion m/z 303, m/z 182 base peak); LC-MS/MS quantification (Waters Xevo TQ-S, MRM 304.1→182.1 quantifier, 304.1→82.1 qualifier); levamisole co-analysis (LC-MS/MS, MRM 205.1→91.1); IRMS for source attribution (Thermo DELTA V, delta-13C in benzoyl ester moiety by preparative GC-IRMS).

Methamphetamine workflow: Marquis test (orange-brown response for amphetamines; weaker than heroin response); GC-MS on achiral column (confirmation, m/z 58 base peak for methamphetamine, m/z 91, 65, 44); chiral GC (Chirasil-DEX CB column, 25 m, 0.25 mm ID; baseline resolution of d- and l-enantiomers at 110°C isothermal; enantiomeric excess reported as % d over total meth); impurity profiling (look for P2P, dimethylamphetamine, phenylacetone, or 1-phenyl-2-propanol to infer synthesis route); LC-MS/MS quantification.

MDMA/MDA workflow: Marquis test (purple-black, slower than heroin); Mecke (blue-green); GC-MS (m/z 193 for MDMA, m/z 179 for MDA; base peak m/z 58 vs 44 for the two compounds); LC-MS/MS tablet content quantification (Waters Xevo TQ-S, MRM 194.1→163.1 for MDMA, 180.1→163.1 for MDA); chiral GC if enantiomeric purity is in question (uncommon in standard casework but relevant in research or pharmaceutical diversion cases).

High-resolution MS for novel stimulants: For novel cathinones or unscheduled designer stimulants, the Thermo Q Exactive or Bruker timsTOF are used for exact mass determination and fragmentation pattern analysis. An exact mass at 5 ppm accuracy within the observed molecular formula allows confident structural assignment even without a reference standard, subject to the caveat that this constitutes a putative identification only.

1. Exhibit intake and physical description
   Record gross weight, physical form (powder, tablet, crystal, rock), colour, odour. For tablets: count, photograph, measure dimensions and individual masses on analytical balance. Sample using UNODC or ASTM E2520 guidance for representative sub-sampling from large lots.
2. Presumptive colour testing
   Scott test for cocaine presumptive (cobalt thiocyanate, glycerine, NaCl solution; blue precipitate in organic layer = positive). Marquis for amphetamines (orange-brown) and opioids (purple-black). Document reaction time and colour. Never skip presumptive: it guides the confirmatory instrument method and is the first step in the SWGDRUG identification tier.
3. Category B screening (FTIR-ATR or Raman)
   Bruker Alpha FTIR-ATR with HATR crystal. Match against SWGDRUG spectral library. For cocaine HCl: 1722 cm-1 (ester C=O), 1601 cm-1 (aromatic). For methamphetamine HCl: 2700-3000 cm-1 (NH2+ stretch), 1600 cm-1 (NH3+ bend). Document library hit score. Note FTIR cannot distinguish enantiomers or confirm cutting agents.
4. GC-MS confirmation (Category A)
   Agilent 7890A GC / 5977B MSD. HP-5MS column 30 m x 0.25 mm x 0.25 µm. EI at 70 eV. Inject 1 µL of 1 mg/mL solution in methanol (cocaine) or ethyl acetate (crack). Match retention time (RT) and mass spectrum against Cerilliant or equivalent CRM. Report all co-detected substances (cutting agents, adulterants, impurities).
5. Chiral GC for methamphetamine enantiomeric ratio (if needed)
   Agilent Chirasil-DEX CB column, 25 m x 0.25 mm. Derivatise with heptafluorobutyric anhydride (HFBA) for chiral resolution. Isothermal 110°C. FID or MS detection. Calculate d:l ratio and enantiomeric excess. Document reference standard RT for each enantiomer from Cerilliant chiral meth standard. Report ee as % d in the certified product.
6. LC-MS/MS quantification and cutting-agent panel
   Waters ACQUITY UPLC + Xevo TQ-S. BEH C18 1.7 µm column, 2.1 x 50 mm. Mobile phase A: 0.1% formic acid in water; B: 0.1% formic acid in acetonitrile. Gradient 5 to 95% B in 4 min. MRM quantification of active substance plus levamisole, benzocaine, lidocaine, procaine (cocaine panel) or amphetamine, ephedrine, pseudoephedrine (meth panel). Report as % w/w with certified uncertainty.